Mobile machines such as haul trucks, scrapers, wheel loaders, and other types of heavy equipment are often used to haul material from a load location at which the material is loaded into the machines, to a dump location at which the material is discarded from the machines into separate piles. In order to maintain productivity and efficiency at a worksite while accomplishing predetermined site goals, travel of the machines at the dump location and positioning of the discard piles should be carefully managed. The need to properly manage the machines at the dump location can become even more important when the machines are autonomously controlled.
One attempt at managing operations of mobile machines at a dump site is described in U.S. Pat. No. 5,931,875 (the '875 patent) issued to Kemner et al. on Aug. 3, 1999. In particular the '875 patent describes an autonomous vehicle system having a resource manager located at a dump site, and a queue manager located on each of multiple dump trucks. The resource manager is configured to manage each of the dump trucks and acts like a foreman assigning tasks to the trucks and tracking their progress as they perform the tasks The vehicle control system permits autonomous operation of each truck under the control of its queue manager.
When a truck of the '875 patent approaches the dump site, the queue manager sends a queue position request signal to the resource manager. In response to this signal, the resource manager sends a queue position signal back to the queue manager and establishes a queue for entry into the dump site. The truck is then stopped at the queue in a location corresponding to the assigned queue position. The resource manager determines a dump point for the truck that is incrementally offset from a previous dump point, and then determines a route to the dump point. Both the dump point and the route are communicated by the resource manager to the queue manager of the truck. The resource manager then determines when the dump point and a row at the dump site leading to the dump point are available to receive the truck, based on a prior truck being finished dumping and having left the dump row. The resource manager then sends a depart queue position signal to the queue manager. The queue manager sends a leave queue position signal, directs the truck to move to the dump point, and sends an arrive signal to the resource manager after arrival at the dump point and initiation of dumping. After completion of dumping at the dump point, the queue manager sends a dump complete signal to the resource manager, which sends back a depart dump point signal. The queue manager then sends a leave dump point signal to the resource manager and directs the truck to leave the dump point. When the truck leaves the corresponding dump row, the queue manger sends a leave dump row signal to the resource manager. When the truck leaves the dump site, the queue manager sends the resource manager a leave dump site signal. Upon receiving the leave dump site signal, the resource manager determines a future dump point for the next truck in the queue.
Although the system of the '875 patent may help manage trucks in conjunction with a dump site, the system may be less than optimal. That is, the system of the '875 patent may have reduced productivity because of limited simultaneous use of the dump site by multiple trucks. In addition, the system may require the trucks that use the dump site to stop and wait for communications of instructions at many different locations. The time spent communicating instructions back and forth between the queue manager and the resource manager could result in disjointed movement of the trucks that further reduces productivity.
The disclosed control system is directed to overcoming one or more of the problems set forth above and/or other problems of the prior art.